Core barrel



Feb. 12, 1929. 1,701,724

1 w. l. MCLAUGHLIN CORE BARREL Filed Feb. 21, 1924 i 1111 FIEA.

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. 45 rotary Patented Feb. 12, '19219.

UNITED STA/TES 1,701,724 PATENT OFFICE.

WILLIAM I. MCLA'UGHLIN, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOIR: TOSTANDARD OIL COMPANY, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF-CALIFORNIA.

CORE BARREL.

Application led February 21, 1924. Serial No. 694,237.

The invention relates to a core barrel for forming and removing a corefrom a hole being drilled into the earth, Core barrels are used inprospecting unproven territory for the purpose of determining the natureand positions of the formation. The present invention relatesparticularly to a core balrrel adapted to be used in prospecting for o1An object of the invention is to provide a core barrel having a coreretainer which is held against rotation by the core and which isprovided with means for definitely indicating the direction of theplunge of the formation from which the core is formed. The inventionpossesses other advantageous features, some of which, with theforegoing, will be set forth at length in the following description,where I shall outline in full that form of my invention which I ,haveselected for illustration in the drawings accompanying and forming partof the present specification. Insaid drawings I have shown one form ofcore barrel embodying my invention, but it is to be understood that I donot limit myself to such form, since the invention, as set forth in theclaims, may be embodied in a plurality of forms.

Reference is made tothe applicants copending application Serial No.714,668 filejd May 20, 1924, which shows subject matter in common withthis application. Referring to said drawings:

y Figure 1 is a vertical section through a core barrel embodying myinvention, a portion thereof being broken away to reduce the size of thefigure.

Figure 2 is a cross section taken on the line 2-2 Figure 1.

Figure 3 is a cross section taken on the line 3-3 Figure 1.

Figure 4 is a cross section .taken on the line 4-4 Figure 1.

- The device of my invention comprises a core barrel 5, preferablycomposed of a pluralityv of cylindrical sectionsserewed together. Theupper section is screwed into the coupling 6 which at its other end isscrewed into a pi e 7 which may con- 0 stitute an extension o the corebarrel or the lower section of the drill tube. Screwed to the lowersection 8 of the core barrel is the drill bit 9 which is providedwithcutting teeth 12, the teeth being arranged in the form of an annulus sothat a central aperture or passage 13 is provided in the drill bit. ",Atits lower end, the section 8 is thickened to ,form a shoulder 14 and theshoulder is provided with a central aperture which is alined with thepassage 13 in the drill bit. On its lower edge the section 8 is providedwith an annular groove .15, preferably semi-circular in cross section,and this groove communicates with the interior of the core barrelthrough the passages 16 formed in the thickened portion. The uppersurface of the drill bit 12 is provided with an annular groove 17,preferably semiecircular in form and of the same diameter as the groove15, so that when the bit is assembled on the core barrel, the twogrooves 15-17 register and fornt an annular passage concentric with theaxis of the core barrel. This assage communicates with the face of therill bit by passages 18 extending downward through the body of the bit.

`Disposed within and preferably arranged concentrically with the corebarrel 5 is a core retainer 21 which is preferably dividedlongitudinally into two halves which are normal1` held together by thebolts 22. After t e core has been formed andthe core barrel has beenwithdrawn from the hole, the core retainer is removed. from the barreland the bolts 22 removed to open the container so that the ycore mayreadily be removed.y This arrangement obviates the possible movement ofthe core with. respect to the retainer after the retainer has beenremoved, so that it is possible to determine the direction of the plungeof the formation from which the core was formed, as will be set forthmore completely hereinafter.

The core retainer is mounted within the core barrel in such a mannerthat the retainer may be held stationary during the rotation of thebarrel. Formed in the coupling 6 is cross wall 23 provided with a seat24l for the ball bearin assembly 25 on which the upper end of t e coreretainer is supported. The plate 23 is provided outside of thecircumference of the bearing member 25 with a plurality of passages 26through which the mud which is introduced into the drill tube may passinto the annular space Abetween the core barrel and the core retainer.

At its lower end, the core retainer is mounted on a ball bearingassembly 27 which is supported on the shoulder 14. By virtue of the ballbearing mounting of the retainer, only a small force is necessary tohold the re'- tainer against rotation during the rotation of the corebarrel. The core retainer is provided adjacent its upper end with aplurality of apertures 28 to permit the ready discharge of mud from theretainer as the core progresses into the retainer.

drill bit is closed by a screw plug 31, screwed into the aperture in thelower end of the lower section 8. The plug is of lesser tainer is heldagainst rotation.

diameter than the internal diameter of the core retainer so that when itis unscrewed it may readily move up into the retainer. The direction ofthe screw thread 32 on the plug is opposite to the direction of rotationof the core barrel and thefplug is provided on its lower face with teeth33 which engage the formation being cut, thereby tending to hold theplug against rotation as the drill bit is rotated. This causes the plugto be unscrewed as the core is formed and the plug leads the core upinto the core retainer thereby preventin the material of the formationbeing cut from enterlng the core retainer. The internal diameter of theretainer is greater than the diameter of the aperture 13 in the drillbit, so that the core is of less diameter than the interior of theretainer and readily moves into the retainer as the formation is cut bythe drill.

The core is not broken or separated from the formation by the drillingoperation so that the core remains stationary and means are provided forconnecting or attaching the core to the retainer so that, as soon as thecore reaches the contacting means, the re- The contacting means comprisea plurality of spring pressed dogs 34 arranged in apertures 35 formed inthe retainer adjacent the bottom thereof. The dogs are mounted on pivots36 secured in the retainer and the ends thereof are urged intotheinterior of the retainer by springs 37. The dogs are provided ontheir inner ends with a plurality of pointed teeth 38 which engage thecore and hold the retainer fixed with respect to the core, so that theretainer does not rotate. Means are also provided for centering the corein the retainer and for roducing marks or scratches on the face of) thecore to indicate rotational movement of the retainer with reoriginalposition with respect to each other may be determined. Disposed in theretainer are a'plurality of resilient pointed fingers 39, the fingersbeing arranged in groups around the inner surface of the retainer andthe groups being spaced apart vertically so that the fingers contactwith the To prevent the drill cuttings from enterx ing the coreretainer, the aperture 13 in the -core at a plurality of places. In theevent that the retainer should rotate with respect to the core, thefingers will scratch a line on the surface of the core and when the coreis subsequently examined, these lines will indicate the extent ofrotation of the retainer with respect to the core. These fingers thuscooperate with the means to be described hereinafter for definitelyindicating the direction of the plunge of the formation from which thecore has been formed.

VAfter the core has been formed the core barrel is raised slightly inthe hole, causing the teeth 38 of the dogs 34 to bite into the core,thus fracturing the core in a substantially horizontal plane andseparating the core from the formation.

Means are provided for definitely determining the direction of theazimuth of the plunge of the formation from which the core has beenformed. Secured to the core retainer so that it is immovable withrespect thereto, is a casing 41, which preferably comprises a doublewalled vessel having the space between the walls vacuumized so that theinterior of the vessel is thermally insulated from the core retainer.The vessel 41 is disposed in a casing 42, the space between the vesseland the casing being packed with a yielding material,y su'ch as cotton,to yieldingly support thel vessel 41 and relieve it from shock. Thecasing 42 is provided with a key 43 fitting into a slot in the upperwall of the retainer and is held in position by a removable bolt 44 setin the retainer and engaging the lower` wall of the casing. Pivotallysupported within the vessel 41 is a magnetic needle 45 which is normallyfree to swing to indicate direction. The vessel 41 is filled with aliquid material which has the property of setting at the end of apredetermined time to fix the needle in position.

While the material is in liquid form, the needle is free to swin and theliquid is of such nature that it will not set until after the lapse of apredetermined time. Assum ing that it requires three and a half hours toenter the core barrel into the hole and form the complete core, theliquid is preferably of such character that it will set after fourhours, so that after the core has been formed,

the core barrel is allowed to remain stationary for about an hour, toinsure the setting of the material to fix the needle in position andthen the core barrel is raised to break the core from the formation.After the core barrel has been removed from the hole and the coreretainer opened, the needle is examined to disclose the positionoccupied by the core in the hole and the core is oriented until it liesin such position, so that the direction of the azimuth of the plunge ofthe formation may be definitely determined. Since the core did not movewith respect to the forma- 'tion While it was being formed, and sincethe core retainer did not rotate with respect to the core, and since thevessel 41 was secured to the core retainer, the needle will indicate theexact position of the core in the earth, so that the azimuth of theplunge may be definitely and accurately determined. In the event thatthe core retainer rotated with respect to the core, during the formationof the core, the amount of Isuch rotation will be evidenced by thescratches made on the surface of the core by the fingers 39, so that bymeasuring the amount of this rotation, the position of the4 needle maybe taken as a basis for the calculation to determine the exact directionof the plunge with respect to the earth. When the magnetic needle isemployed for determining the direction of the plunge, the core barrel 5,the core retainer 8, the coupling 6, the length of tubing 7 and allother parts of the structure with the exception of the drill bit and thebearings, should be made of paramagnet-ic material, such as bronze, sothat the needle will not be deflected from its proper position by theinfluence of the material of the core barrel and its structural parts.When the magnetic needle is not used, the entire structure may be madeof steel.`

I claim:

1. In a core barrel, a core retainer and a plurality of resilientfingers secured to the retainer at vertically spaced points and eX-tending into the core retaining space adapted to center the core in theretainer as it progresses into the retainer.

2. In a core barrel, a core retainer rotatable with respect to the corebarrel, means adapted to prevent rotation of the retainer with respectto the core and means carried by the retainer for indicating thedirection of the azimuth of the plunge of thestrata of which the core isformed.

3. In a core barrel, a core retainer, means tending to prevent rotationof the retainer with respect to thecore, means for indicating'the amountof rotation of the retainer with respect to the lcore and means forindieating' the oriented position of the retainer with respect to theearth when the core is broken from the formation.

4. In a` core barrel, a core retainer, means for determining theposition ofthe retainer relative to the earth, and means for indicatingthe amount of relative rotation between the retainer and a fracturedcore within the same. i

5. In a core barrel, a core retainer, means for indicating the ositionof said retainer relative to the eart and means for marking on they corewithin the container to indicate the amount of relative rotation betweenthe retainer and the core.

6. A core retainer comprising a cylindrical member, and means forcentering the core comprising a plurality of yieldable fingersprojecting from the inner wall of said cylindrical member atlongitudinally spaced points.

7. In a drilling device of the rotary core type, the combination ofmeans for severing the core, and means a plied to the core at aplurality o f longitu inally spaced points for centering the core withinthe device.

8. In a device of the class described, a core barrel, a core retainerfreely rotatable 'within said barrel, means for causing said retainer toremain substantially stationary with respect to a core during rotationof the,

